The Big Sandy Mountaineer -

On February 21, the MSU Extension Chouteau County office will be moved to the green steel building located next to the Chouteau County Courthouse. The original Extension office located in the Courthouse basement will be filled by Judge Susan Spencer from Chouteau County Justice of the Peace.

Winter Tree Watering

Winter watering is next to useless when the soil is frozen or soil temperatures are below 40 to 45 F. Plants can’t absorb much water in winter, and they need less of it. It is better to water in spring, when the buds really begin to swell and show green tissue or in the fall after leaves drop and before soil freezes. It’s natural to be concerned when you see evergreen needles discoloring or the branch tips on deciduous trees and shrubs drying out, but watering your plants may not always be a good thing. When the soil freezes, dormant plants will be less damaged by the deep cold than plants that are not dormant.

Most woody landscape plants will not grow much at air temperatures below 45 F and even if we have a couple of days with temperatures above 45 F, they still may not respond. Once temperatures get into the 50s and 60s continuously, plants should be watered.

Soil temperature is another factor to consider. When the ground is frozen, water can’t get into the root zone. Even when the ground isn’t frozen and the water can reach the roots, plants can’t absorb much of it unless they are actively growing. The roots of most woody landscape plants don’t begin to active growth until soil temperatures are above 45 F. Average soil temperatures throughout much of the state don’t reach 45 F until mid-April and as late as May in some areas.

Another reason trees and shrubs don’t need as much water in the winter is that they don’t lose as much through their leaves. Deciduous plants have no foliage in the winter, so the rate of water loss is minimal. Since evergreens retain their leaves, they lose more water than deciduous plants. That’s why watering your evergreens in the fall is more critical.

When should you water? The time to begin watering is when plants have come out of dormancy and are beginning to grow. At that time the plants need at least one inch of water per week. What exactly does “an inch” of water mean? It means the plant needs an amount of water that would form a layer 1 inch deep over the surface of the root zone. Of course, the water will seep into the ground as you apply it, but if it didn’t, the layer would be an inch deep.

If you would like to learn more about transpiration and water needs of plants, there is more information available at the Extension office, which is located in the green steel building next to the courthouse.

Montana State University U.S. Department of Agriculture and Montana Counties Cooperating. MSU Extension is an equal opportunity/affirmative action provider of educational outreach